Telephone-exchange system



June 9, i925.

D. L. TEMPLE TELEPHONE EXCHANGE SYSTEM Filed Nov. 28, '1922 QQ m Qu@ Wwf/#af @a/JL 755/77//63 l n, 2 n m. 5 mW 1 v m m dal. .n .l S NQN s @Imm Y kw .Ill

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June 9, 1925.

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D. L.. TEMPLE TELEPHONE EXCHANGE SYSTEM Filed Nov. 28 1922 5 Sheets-Sheet .'5

Patented June 9, 1925.

, UNITED j, STATES' PATENT OFFICE.

DAVID L. TEMPLE, `OE NEW YORK, N. Y., AssIGNoR To WESTERN ELECTRIC COMPANY, INCORPORATED, or NEW YORK, N. Y., A CORPORATION OP NEW YORK.

TELEPHONE-EXCHANGE SYSTEM. y

Application filed November as, 1922. serial No. sos-,75.4.

To all whom 'it may cof/warn1 l Be it known that I, DAVID L. TEMPLE, a citizen of the United States of America, residing at New York, inthe countyof .New York and State of New York, haveinvented certain new. and useful Improvements `in Telephone-Exchange Systems, Y of which. .the followingis a full, clear, concise, and exact description.v A .f

This invention relates to a telephoneexchange system s and more, particularly; to n a system in which connections are'extended between subscribers lines .by vmachine switching equipment. f, v

Subscribers line,V ofa telephone exchange system yare customarily divided .into service groups in accordancef'with 'Y the manner in which the subscribers are `to be charged .for service, that is, certain of the lines, known asflat rate lines,.are permitted to makeany number of calls within the'exchange area for afixed monthly rate, and Other. lines are permitted a fixe-d number of calls permonth at afixed rate, and are charged additionally for all calls in excess of such number. Lines of this latter classare equipped atfthe central oflice with individual message registers for registeringzeach successful call in `order that the telephone company may be enabled to make an additional chargeffor all calls in excess of the fixedA monthly number. A third class of lines, usually terminating in pay. station booths, are provided-.with coin boxes in which the calling subscriber is required todeposit a coin ortoken before obtaining a desired connection, .the coin being collected if the call is successful and refunded if it is unsuccessful.. 1

AIn all exchangeareas there are certain lines to. which it isdesirableand equitable to permit the extension of connections without charging the Acalling subscribers for service as by eitheroperating tthe Asubscribers message registeror collecting a deposited coin or token. Such lines, for example, are lines extending tothe commercialioflices of the telephone company, -to lire stations, police stations and hospitals.v In exchange areas where all connections areV extended manually by, operators, it is obvious that the operatorsv can takethe necessary steps to prevent the charging of such free line calls against calling subscribers as vby refunding the coins deposited or by preventing the operation of the calling subscribers message registers. o

In exchange areas in whlchl connections are extended by machine vswitching mechanism,rhowever, it is necessary to` provide some means which will function automatically to give free service onconnections to lines of the character above enumerated. This has usually v been accomplished heretofore by the segregation of all lines of a free service character and by terminating them in the terminal lbanks of certain final switches, such final switches being arranged to. omit the usual service charge operation. With this/method of handling calls to free lines, it .is therefore necessary to reserve an entire frame of switches having terminal facilities for from `one hundred to five hundred lines depending upon the type of final switch used, whereas the number of such freelines in any given olice rarely'exceeds fifty. It is'thus apparent that such final selector switches are not efficiently employed andthat a great. economy in apparatus may be effected by terminating-all klines alike in the banks of regular linal switchesand supplying equipment individual to such free lines for 'nullifying the. call chargingoperation. Y, .f It is, therefore, the object ofthe present inventionto enable calls to be extendedto certain lines' without chargingthecalling subscribers therefor, through the provision of means individual to leachfof such-certain lines." g

.'.The principal feature of thisinvention resides in the provision of a circuit whichmay be inserted between a set of terminals inthe final selector switch and the external circuit of. a line, connections to which are yto be .given without charge tothe calling subscriber. This circuit is arranged to trip machine ringing, and to applyringing current to the called. line without causing such changes in the exchange circuits: as will chargefthel calling subscriber for the call.;

This and other features of the invention will be apparent from consideration ofthe tangle for controlling the operation of the" district selector and the other switching apparatus of the exchange through which a connection may be extended. Fig. 2 lshows a portion .of the circuits of `an incoming selector sw'itc'h and vfinal select-.or` switch. Fig.

3 shows a circuit forming the basis for this invention, connected between the terminal banks of the final selectors of Figs. 2 and 4 and the line of a subscriber to which connections are to be permitted without charge, a diagrammatic representation of a portion of such called subscribers line switch and the line of a subscriber, connections to which are charged for inthe usual manner. Fig. 4 shows the calling -end of an operators cord circuit, a portion of a cordless incoming selector circuit and a diagrammatic representation o a llinal selector switch by means of which a connection may be extended from the operators position to the subscriber's lines disclosed in Fig. 3. Description .of apparatus md general method .of operation.

The line switch 106 of Fig. 1, is of the well-known step-by-step type controlled by magnet 102. The district selector 150 is of the sorcalled panel type shown in the patent to E. B. v(haft and J. N. Reynolds, 1,123,696 issn'ed January 5, 1915, but disclosed herein in a simplified form for the purpose ofsimplifying the disclosure of this invention. This switch has been illustrated as having Y but 'a single set'of brushes '147, the assumption being `made that the switch may be set to a desired group of terminals by a single selective movement und-er the control of the lip-drive magnet 143. The selector `switches 200, 250, 260 and 270 disclosed in Figs. =2 and 4 may also be-of the type shown in the aforesaid patent.

The sequence switches 198 and 232 associated with the district vselector 150 and with the incoming selector l200 and the sequence switch associated with the final selector switch 250, sorne of the cams pf which have been illustrated, are of the well-known type disclosed in the Vpatent to J .N. Reynolds and C. ,F Baldwin, 1,127 ,808 issued February 9, 1915. For a 4complete description of the manner in which the apparatus disclosed lin Figs, land 2Aunct'1ons, reference may be had to Patent 1,395,977, issued November 1, 1921 to F. A. Stearn and F. J. Scudder. Since the operators cord circuit. and the cordlessposition apparatus shown in Fig. 4. enter only incidentally into the disclosure of the present invention, it has not been thought necessary to show them in detail. Avfull disclosure and description of these circuits may be found .in the ap plication of J. W. Gooderham, Serial No. 417,422, led October 16, 1920, Pat-.ent No. 1,506,743, sept. 2, 1924.

'The free line circuit shown in Fig. 3 is disclosed as inserted between the terminal banks of the iinal selec-tors 250 and 270 and an external line service toward which is to be accorded withoutv charge. This circuit separates the subscribers line from thev switch terminals by condensers, which prevent the establishment lof a direct current bridge across the tip and ring brushes of the selector, upcn the response of Ithe called subscriber. Briefly, when 4the free line vis seized, a slow-tofreleas'e tripping relay 300 is operated over the tip 4conductor of the circuit from ground lapplied at the incoming selector 200. This relay prepares al circuit for applying battery current to the ring' conductor of thecircnit for operating the ringing vtrip relay 230 at the incoming selector andcauses the application Vof ringing current to the called line on the outgoing side Vof the condmsers.v Upon the application of ringing current to the called line, the circuitprepared by 'the slow releasing relay 300 is rendered elective for operating the ringing trip relay 230 and the y circuit of yrelay 300 is opened so that the tripping circuit is effective only during the releasing period of slow-.to-releas'e relay 300. Upon the response ofthe called subscriber, the ringing current suppliedfto his line is cut oil and-talking current `is supplied to the called line through supervisory relay 301. The closure .of the circuit over the ring conductor ,o the Jfree line circuit `for tripping ringing current at ,the incoming selector, While applied for a .sufficient period to .trip-the ringing current is not applied for a suilicient period to `cause an effective reversal of current tcthe district select-.0r to operate and lock the charging relay 1.68. Thus, no charge is registered against the calling subscriber for the connection.

Having now briefly described the invention and the apparatus employed ity is thought that ya clearer understanding of the invention will be had Vtrom a more detailed description of the manner in `which lthe invention is practiced. 'Accordinglyb "a description will first be given of the manner in which a calling subscriber A establishes a connection with the line of subscriber B, it "being assumed Athat the calling subscriber is to be charged for such connection, A de-V llO The calling subscriber A' to initiate the establishment of a connection with the subscriber B, removes his receiver fromthe switchhook whereupon a circuit is established for the line relay 100 extending through the armatures and contacts of the cut-off relay 101 over the calling line loop. Line relay 100 upon energizing establishes a circuit for the stepping magnet 102 which in the well-known manner advances the wipers 103', 104 and 105 of the line switch 106 over the terminals of trunk lines eX- tending to district selector switches. As soon as an idle district selector is found, a circuit is established for the cut-olf relay-101 of the calling line, which may be traced from battery, through lthe operating winding of relay 110, camY contact 111, bank terminal 109 and'test Wiper 105 of'line switch 106, to ground through 'the winding of cut-off relay 101l and the winding of message register magnet 112. Relays 110, and 101 energize infthis circuit but magnet-112 being marginally wound, does not receive 'suihcient current at this' time to energize." Upon the energization of cut-off relay 101, the circuit of the subscribers line relay 100 is opened 'and the advance vmovement of the line switch is thereupon arrested. 1 Relay 110, upon energizing closes a circuit for advancing sequence 'switch 198 vof l the selected district selector 150 out of position 1 and intopositionl 2, which circuit eX- tends from battery through the magnet winding of sequence switch 198,'cam contact 113 (1) and to ground at the right armature contact of relay 110. With sequence switch 198 in position 2, a circuit is established for the stepping magnet 116` of the sender finder switch SF, for advancing the sender finder in search of an idle office sender. 'The circuit of stepping magnet 116 may be `traced fro-m battery `through the winding and armature'contacts ofv magnet 116, cam contact 117 (2) and thence tlO ground at the left armature and contact of relay 118.'V yDuring the. hunting movement of sender finder SF, test wiper 119 advances over test'terminals of' oflice senders until the wiper 119 engages the Itest terminal ofan idle sender, when a circuit is 4esvc-'a'blished for relay 118 extending from battery Vthrough the winding of thisrelaywiper 119 and terminal 120 to ground. Relay 118 upon energizing opens thev` previously traced circuit of stepping magnet 116 thereby arresting the movementlof'the sender iinder yand.

closes' a circuit for advancing sequence switch 198 into position 3, which circuit extends from battery throughthe magnet winding of the sequence switch, cam contact 121 (2) `and to ground at the right armature contact-'of relay' 118.

Upon the association ofv an idle oice-l sender with the selected district selectory an impulsing circuit is established betweent-he office sender and the calling line over which circuit the calling subscriber is enabled, through the operation of his calling dials, to register the number of the desiredline upon the registers ofthe sender, in the manner fully set forth in the patent to F. A. Stearn and F. J. Scudder, 1,395,97 7 referred to hereinbefore. This impulsing circuit .may be traced from battery, .through the register stepping relay 123, wiper 124, vconductor 125, the left contact of cam 126 (1 to bank terminal 108, Wiper 104,l thence over the calling subscribers line loop, through his calling dial S, wiper.`103, bank terminal 107, lower contact of cam 12,7 v(1 to 3), conductor 128, wiper 129 andl thence to ground. 'y

With sequence switch 1 98 in position 3, a fundamental circuit is established between the vcontrol relay"131` of the district selector 150 andthe SelectedoiiiCe sender, which may be .traced from battery, through the winding of control .relayy 131, cam contact 132 (3) conductor 134, wiper'13`5, winding of' sender stepping relay 136, the contact of cam 130, which cam is associated with a sequence *switch (not shown) of the oflice sender,`the armature and back contact of counting relay 137, ywiper 138, conductor 139,' and thence to Y ground at cam contact 140 (3 to 4) Relays 136 and 131 energize in this circuit, relay 131. closing a locking circuit for itself through its left armature, 'cam contact 133 (3 to 4) and thence'to conductor 134 and over the fundamenta-l circuit previously traced. At its right armature and front contact vrelay 131 closes a circuit extending through cam contact 142 (3) and conductor 141 for advancing sequence switchy 198 into position 4.

llVith sequence vswitch 198 in position 4, a circuit is established for the np3-drive magnet 143 for advancing the brush set 147 of the district selector 150 inseanch of a grouip of trunk lines extending to the office of the exchange in which the desired line B terminates. vThe circuit of magnet 143i may be traced` from battery, through the winding of magnet 143, calm contact 144 (4),and to ground at the right armature and front contact of relay 131. Magnet 143,v'u-pon energizing, presses the depending portion of 'switch shaft 145 against the constantly rotating up-drive roller 146, whereuponv the switch shaft and the attached brush set 147 are driven upwardly.

VAsthe brush set 147V approaches a posi tion immediately beneath the first group of bank terminals, shaft wiper 148 engages a conducting portion of commutator 149, whereu|pon| a circuit is closed in shunt of the winding of sender stepping relay 136 which may be traced from battery, through the winding of control relay 131, the left armature and front contact of relay 131, cam contact 133 (3 to 4), cam contact 151 (4), conductor 152, co-minutator 149 and thence to ground through wiper 148. In response to the establishment of this circuit, sender stepping relay 136 deenergizes and in the well-known manner controls the circuits of the sender to count one impulse on the counting relays of the sender.

As the switch shaft 145 continues in its upward movement, the shaft wiper 148 engages an insulating portion of commutator 149 and the previously traced shunt circuit is thereupon opened again permitting the energization of sender stepping relay 136. Thus, during the continue-d upward movement of the switch shaft, the sender stepping relay 136 is intermittently energized and deenergized until the lcounting relay 137 becomes energized, when the oliice sender will be satisfied? with respect to the ofhce registration of the desired subscribers line. Upon the energization of relay 137, the previously traced fundamental circuit is opened thereby opening the circuit of control relay 131 and advancing the sequence switch of the sender to a position in which it controls the next selection. As soon'following the lopening of the` fundamental circuit as the brushes of brush set 147 are centered upon thel lowermost set of bank terminals in the selected group, shaft wiper 148 will engage an insulating' portion of commutato-r 149 and relay 131 will become deenergizedi, open-- ing the circuit of up-drive magnet 143 to arrest the upward movement of the switch shaft, and closing a circuit extending through cam contact 153 (4) and over conductor 141 for advancing sequence switch 198 into position 5.

With sequence switch 198 in position 5, the circuits of the district selector are prepared for the control thereof its hunting movement for selecting an idle trrmk in the selected group of interoiiice trunks. A circuit is now established# for relay 131 extending frombattery, throughl the winding of this relay, cam contact 132 (5), and to ground at -caun contact 154 (5), and at its right armature and front contact closes a circuit Vextending over cam contact 142 (5), and conductor 141 for advancing sequence switch 198 into position 6.

Under the assumption that the first trunk of the selected group, upon the bank terminals of which the brush sert 147 is now resting, is at the time busy, relay. 131 is .maintained locked after sequence switch 198 leaves position 5, over a circuit extending through the left armature and contact of relay 131, cam contact 133 (5 and 5), cam contact 155 (5l/2 to 10), test brush 156, test terminal 157 and thence over multiples of test terminal 157, through the test brush 156 of a district selector similar to selector 150, which is at the time in engagement with the multiples of this trunk and to ground at a cam Contact corresponding to cam contact 163.

With sequence switch 198 in position 6, the circuit of up-drive magnet 143 is again established over cam contact 144 (6) and the switch shaft 145 is again driven upwardly inV search of an idle trunk in the selected group. So long as the test brush 156 engages the test terminals of busy trunks, the locking circuit of relay 131 is maintained and the circuit of up-drive magnet 143 remains closed. As soon, however, as test brush 156 engages the test terminals of an idle trunk, which it will be ssumed is the trunk terminating in bank terminals 158, 166 and 167, the previously traced locking circuit of control relay 131 is opened and when the brushes of brush set 147 become centered upon the bank terminals of such idle trunk, relay 131 deenergizes. Until the brushes are s o centered, relay'131 is maintained locked over its left armature, cam contact 133 (5 to 6), cam contact 161 (6), conductor 162, centering commutator segment 160, and to ground on shaft wiper 159. Upon the deenergization of control relay 131, the circuit of the up-drive magnet 143 is opened to arrest the upward move- 'ment of the switch shaft, and a circuit ,is established over cam `contact 153 (6') and conductor 141, for advancing sequence switch 198 into position 8, in which position conductors 134 and 139 .of the fundamental circuit extending to the office sender are connected over cam contacts 174 and 175 to the brushes 165 and 164 of the district selector 150. e

During the setting of the vdistrict selector switch 150, relay 168 is maintained energized over a circuit extending from battery, through the winding of relay 168, the lefthand contacts of cam 169, wiper 170, armature and back contact of advance relay 171 of the oflice sender, and to ground at cam contact 172, and at its right armature and contact closes a circuit for energizing con.- trol relay 131 which is effective as soon as a sequence switch 198 reaches position 8. This circuit extends from battery, through the winding of relay 131, cam contact 173 (8) and to ground at the right armature of relay 168.Y Relay 131 is maintained energized until the office sender has functioned to completely establish the desired connection. With sequence switch 198 in position circuit to the incoming selector switch 200,

a circuit is V'closed from battery,` through the right windingfof relay 201, the right contacts of cam 202 associated with the sequence switch 232, conductorv 2.03, resistance element 204, the upper contact ofv cam 205 (1 to 10) trunk conductor 206,bank terminal 167, brush 165, cam contact 174 (7 to 8), conductor'134,'wiper 135, winding of senderstepping relay 136, cam contact 130,

the armature and Vcontact of counting re-v lay 137, wiper 138, conductor 139, cam contact 175 (7 vto 8), brush 164, bank terminal 166, trunk conductor 207, the lower contact of cam 208 (1 to 10), resistance element 209 and-thence to ground at the lower contact of cam 210 (1 to 8). Relayl 201 energizes in this circuit and at its armature and front contact closes a locking circuit for itself extending t-hrough its right winding, lower contacts of sequence )switch camv 202, the right armature and vcontact of relay 201, the contacts of sequence switchcam 211 (1- to 4), thence as previously v'traced over the fundamental circuit. Relay 201 also, in the well-known manner advances sequence switch 232 to a position in which the switch shaft of the selector switchisl advanced in its brush selection movement under the control of the office sender.

During the upward movement of the shaft ofthe incoming selector switch, the Isender steppingy relayV 136 is intermittentlyv energized and deenergized in the well-known manner to energize and lookup successive pairs of counting relays until the office' sender is satisfied with respecttotheoflice brush registration set up thereon by the calling' subscriber, when the counting relay 137 becomes energized and the sequence switch of the sender is advanced to the position in which it controls incoming group selection. Following the operation of relay i137, control relay 207 of the incoming selector deenergizes and in the well-known manner advancessequence switch 232to arrest the upward movement of the'switch shaft. i

Upon the' termination vof the brush selection movement of the switch shaft of the incoming selector switch, a tripping magnet (not shown) is operated to trip the selected set of brushes upon a subsequent upward movement of the switch shaft and thereafter in the well-known manner the selected set of brushes is advanced to a predetermined group of bank terminals in accordance with the setting of the thousands and hundreds registers of the ofhcefsender. l v Upon the completion of the groupyselection movement of the incoming selectorl switch,`the circuits ofthe incoming selector function in the well-lmown manner to select i a ktrunk extending to, an Vidle final' selector switch. As soon as such idle trunk is found, the lsequence switch 232 of the incoming selector 'advances in thev'well-known manner to position 8, in which positionthe fundamental circuit is extended to theffnal selector switch. The fundamental circuit may be tracedV in part from ground at the lower contac'tf'of cam 210 through resistance element' 209,- the lower contact ofhcam 208 (1 to 10), trunk conductory207, thence as previously traced to the oflice vsender and through thelwindingof sender stepping relay 136," and returning over conductor 206, the upper contact of cam 205 (1 tov 10') resistance element 204, conductor 203, the upper left contact of cam 212 (8), brush 213 of incoming selector switch 200z and thence through the control relay (not shown) of the selected final selector switch 250, to battery. A holdingl circuit is also established at this time v,for relayl 201 which may be traced from battery, through the right winding of relay 201, the lower contacts of cam202, right armature and front contact of relay 201, the lower'contact of cam 2l4 to 8), brush 215, bankterminal 235, and thence to groundthroughfthe upper left and' lower right contacts yof cam 216. VThis holding circuitr for relay 201 yis 'maintained until the sequence switch of the inal selector .leaves position 81/2 'voruntil all of the the setting of the4 hundreds, tens'and units registers oftheoflice sender in the manner fully set forth in the patent to FLA. Stearn and F. J.l Scudder, l 1,39; ,977 hereinbefore 'referred to. lThe called line is -nowY tested and if found to be idle, the sequence switch of the final selector advances into the talking position 15. y v

vAsv soon as'units selection is completed and the sequence switchassociatedwith the final selector switch leaves position 8%, the previouslytraced holding circuit of relay 201 is opened at the lower contact of cam 216 and relay 201 in the well-known manner, causes thefadvance of sequence switch 232`asso'ciatedv with'the incomingk selector 200 kout of position 8 into position 9. With sequence switch 232 in position 9, battery and ground at the incoming selector .are reverselyconnected to the `conductors'206 and 207 of the trunk circuit extending back to the district selector, andthe oiiice sender is thereupon 'caused to function in the wellknown manner to operate the advance rezlay 171. The control relay y201 at the incoming selector, also energizes l invthfis circuit #completed its functionsy and relay 171 is 201,y the right contacts Yof@ cam 202, con-YY ductor 203, i'esistance element 204,Y upper angl advances, sequence. ISaiten 232, out of position I9 into psitonlOi. Y

Silie at. this-time, the loiiice sender has Operated, the shiu'itsisiemoved from around resistance element 176 and the currentv now Howing rthrough the winding ot marginal relay 168 is reduced to A'such yan extent that this relay deenergizes, openingthe circuit of relay 131. VRelay 131, upon vdeencrgizing, closes av circuit extending over cam contact153 (71o 8).- and conductor 141 for advanci'n'g ys"equenceswitch 198 into position 10.l The oiiice sender is'no'w restoredin the wellfknown manner and disassociated from the district" selector switch 150I whereupon it is renderedV` available for use in establishingrk other connections.

Withe'quence switch 198 in position 10,Y

relay 201 of the incoming selector is energized -`over a circuit which may be traced from batterywthrougll .the right winding of relay ContactY of cam 205 (1 to 10), trunk conductor 206, bank terminal 16,7, brush 16o, cani contact 177 ('10), the Aupper right wind ing of' repeatingvcoil 17 8, the Winding of polarized relay 179, the lower right Winding of repeating coil 178, lcani contact 180 (10i), brush 1564, .bank terminal 166, trunk conductor, 207, the lower` contact of cam 208 (1 "to 10) resistance element 209, thence to g'ouhd at the lower contact 'of camu 2 10 10),. Current 'iowing in ythis circuit w'hile in s iich a direction as yto energize relay201 does not flow through the windingv of polarizedrelay l179Vin such `a direction as to cause its effectiveY energizvation. Relay` 201 upon energizing causesf'the advance of sequence sii/itch 232 into. position 11 in the wellknown manner. Y, y

With seduencefswitch Y232 in position 11, relay 201 is held: energized over a circuit which may be traced from battery, through its left winding, the armature and Vback contactof marginal ringing ltrip relay 230, the contact of sequence switch cam 229 (10 toi 18), the inner left armature and front contact of relay `2,01, the v'upper Contact of cam 228 (2 tof1`8), sleeve conductor 227, bank terminal 158, b'ruslr156 tovrground at cani contact 163. ('7 130,17). Ringing currentfis "now aoplied te the called line B, it being l'assumeilethat the final selector 250 `found this line to be idle, over a circuitV which may be traced fromfthe source of ringing'current231 through the winding ot relayf230, th'efleft contacts of cam 20.2 (11 toy 13), the "right armature 'and contact. of relay tenths fimver contacter Cam 214 (n to y14) brush A215, bank r"terminal 235,` lthe n'pperrcontacts -of cam 216,v :brush '221 land vbankterniin'al -23.601 the yfinal selector 250 thence over the line of 'the called subscriber B through thevringer 302 returning over bank terminal 237, and brush 224 'of the final selector 2.50, the lower contacts of cam 225, bank terminal 226 and,y brush 213 of the incoming selector 270,0 to ground at the Yright Contact of @am 212 (11 teiel). y

Upon the nisponsel of the called subscriber, marginal relay 230Y energizes andrat` its armature and back contactopens the holding circuit o1' relay 201. Relay 201 thereupon deenergizes, opening the circuit Voyer which ringing currentwas applied Yto, the called line at its right armature and `front Contact, and at itsy outer leftarmature and back contact closing` a circuit for causing the advance of sequence switch 232 out of position 11 into the talking position 16. With sequence switch 232 in position 16, a circuit is closed for supervisory relay 219 which may be traced from the non-grounded terminal of battery, through the lower right winding of repeating coil' 220, relay 219 the upperY contact of cam 214 14 to 16) thence over thesub'scribens line loop as previously traced, returning through the lower contact rightY winding 'of repeating coil 220. .Relay 219 energizes in this 'circuit Vand closes a circuit which Y is effective for 0,pe1'c`ating` the polarized relay 179 which maybe traced fromV battery, the upper contact of cam 210 (151 to 16'),v resistance element 209, upper 'contacts oi cam 217 (11 to 16), lower left winding of repeating coil'220, the upper contact of carn208, (11Y to 16), trunk vcon'- ductor 207, bank terminal 1646, 'brush 164, cam contact 180 y"(10"), the lower right winding` of repeating coil 178, the lwindings 'of relay 179, the upper right winding of reL peating coil 178, cam contact 177 (10'), brush 16,5,y bank terminal 167', conductor 206', the lower`contact of cam 205l (11 to 16), the upper left winding of repeating coil 220, resistance element 204, conductor 203, YYthence to' 'ground at the armature contact of relay 219.

A circuit is now established at the district "selector for relay 181 which may be traced fro-'m battery over contact182 of the 4 independently of cam contact 182 and prel pares a circuit for charging relay 168 which is 'effective as soon as vthe circuit cam moves to-y such a position as to cause the closure of its' contact 185. Relay 16811po'n enerH gi'zing, closes a locking circuit lfor itself' extending 'over the upper contacts of cam 169 Iand to ground throughl its lown right arIna- Ature contact, and at' its left armature contact prepares av circuit over 'conductors 190 and' 191, which iseffeotive Jfor "charging a call on the calling subscribers message register 112 following the termination of the conversation and the movement of lsequence switch 198 into position 17. Y

, The calling subscriber A is now connected in a conversational circuit with the line of subscriber B over the conductors shown in heavy lines in Figs. 1, 2 and 3,-the calling subscriber receiving talking current through the left windings of repeating coil 178 and throughthe winding of supervisory relay 186 and the called subscriber receiving talking current through the right windings'of repeating coil 220. During the continued establishment of the talking circuit, thev supervisory relays; 186 andY 219 are maintained energized over the calling and called lines respectively. Y Upon the termination of the conversation, the subscribers restore their receivers to their respective switchhooks whereupon relays 186 and 219 become deenergized. Relay 186 upon deenergizing closes a circuit extending overconductor 187 and cam contact 188 to 16,) for advancing sequence switch198 out of position 10 and into position 17. As soon as sequence switch 198 leaves position 161/2 the previously traced circuit for relay` `110 is opened atcam contact 111, but relay 110 is maintained energizedover a circuit extending from battery through its' right operating winding, conductor 191, left armature Contact of relay 168, conductor 190, cam contact 189 (17) bank terminal 109 and wiper 105 of line switch 106, .and thence to' ground ythrough the windings of cut-off relay 101 and message register magnet 112. Battery current is also connected through the winding yof message register magnet 112 from .battery through camcontacts 192 and 193 .closed in position 17, the left armature land contact and left non-inductive vwinding of relay 110, thence to ground throughrthe winding of magnet 112. over the circuit previously traced. Magnet 112 nowreceives sufficient current to cause its energization .thereby causing lthe registration of a call on the calling subscribers message register.

With sequence switch 198 in; position 17 a circuit is now established for relay 131 which may be traced from battery, through the winding of relay 13.1, cam contactv 132 (17) and thence to ground through cam contact 154 (17). Relay 131 upon energizing closes a .circuit over cam contact 142 (17) and conductor 141 for advancing sequence switch 198 out of position 17 into position 18. As soon assequence switch 198 leaves position 17 the circuit previously traced. through the windings of cut-off relay 101 and the message register magnet 112 is opened at cam contact 189, and the circuits associated with the calling subscribers line andl individual line switch varejthereupon restored to normal position in the wellknown manner.

v With sequence switch 198 in position 18, a circuit isestablished for the down-drive magnet 194 extending through contact 19.5l (18). This magnet, upon energizing, presses the depending portion of switch shaft 145 against the down-drive roller 199 thereby causing a downward movement of the switch shaft into normal position. vAs soon as the switch shaft reaches its normal position, shaft wiper 148engages normal commutator segment 196, and a circuit is vestablished from ground4 on wipe-r 148 throughsegment 196, cam contact 197 (18) and over conductor 141 forv advancing sequence `switch 198 in' normal position. The circuitsof the district's'elector are now in normal position. y' y l As soon as sequence switch198 leaves position 17 busy ground potentialis removed fromxthe test terminal 158 of the selected trunk 206, 207 and the restoration of the incoming and final selector switches to their respective normal positions is initiated. All of the apparatus employed in the establishment of the connection is now in condition to be taken for use in establishing other connections.

Establishment of a connectioncallz'ngsubsomber accorded freeV service.

It ywill now be assumed that the calling snbszriberAl desires a lconnection with the line C fork which Vconnection he should not be charged. The calling subscriber will proceed as hereinbefore described to dial the designation of the desired-linev whereupon the central office sender shown in Fig. l causes the operation of thedistrict selector 150,A the incoming selector. 200 andthe Vfinal selector 250 to make connection with the terminals 222, 223, 239- of the desired line C .in the manner hereinbefore described.

. When the brushes of the final selector switch 250 becomes positioned upon the terminals of the desired line, .it being assumed that the line is at the time idle, a circuit is established for the vsleeve relay 304, which may be traced from battery through the test brush 238` and bank terminal 239 of the final selector switch, conductor 240, the normal contacts of make-busy .relay 303 to ground through thewinding ofrelay 304. Relay 304, upon energizing, closes a circuit over the front' contact of its inner right armature, through the winding of make-busyrelay 303 to ground and in parallel over conductor 305, resistance 306 to ground through the windings of the cut-off relay 307 of the called line. Relay 304 Aupon energizing-also disconnects'battery at theback contactof its left armature and closes a locking circuit through the front contact .of this armature extending from ground through the winding of relay 304, the alternate ar1nature contacts of' relayy 303 and thence over conductor 240 to battery at the i-i-nal selector switch. In this manner, the called line is made busy to all other final selectors which have access thereto. At its inner right armature and con-tact, relay 304V also prepares' a circuit for the ringing relay 314 which becomes eiliective uponv the energization of relay 300. At its outer right arma-- ture and contact, relay 304 prepares` a circuitl for the tripping relay 300 which beL comes effective as soon as the sequence switch of the inal selector 250I moves into its talking position and' as soon as' the seqnence switch4 232 of the incoming selector advances into position 11 for ringing as hereinbefore described.

Vith sequenceswi-tch 232 in position 11 and the sequence switch of' the final selector switch inI` the tall-ring position 15, the circuit of' relayy 300 may be traced from ground at the righ-t contact of caniv 212 ('11 M131/2,), brush 213, bank termin-al 226, the lower contacts ol?` cam 225, brush 224, bank terminal' 223,4 conducto-r 3081, conductor 309', the armature and-back contact of relay 310, conductor 311, the outer right armature and* contact. of` relay 304,. the Winding of relay 300 to battery at. the outer. left. armature and back contact of relay 312.

l yWith relays 304 and 300` both energized, the circuit of ringing relay 314 is established and mayI be traced" from battery through the inner right armature and: contact of relay 304, conductor 315, the' winding-of ringing relayv 314, conductorV 3l3`to ground at the left armature and front contact oct relayl 300.- vRelay 3141, upon ener'- gizing,` closes a locking circuit for itseli1 eX'- ten'ding' from battery on conductor 315, through the winding of relay.3-14, the outer right, armature andl iront contact oit relay 314,'t`o' ground at the; armature and back contact of'riiiging-cut-oif" relay 3117i Relay- 314 is' thusn maintained energized independently ofltlie operation off relay 300i until' the called subscrilen responds` to,I t-he application of ringing current. Relay VV314 at its inner right' armatureand front contact closes a circuit forl relay 3112 which may be traced fromA battery' throught-he inner right `armatureiandf' contact vofrelay 304, conductor 3115, tlie-inneriglit armature andcontact of relay 314tox ground through tlie winding of relay 3122 Relay/312 now energizesand locks t'obattery` over4 conductor 305l indefpend'entl-y ofi" the contacts ofringing relay 314. With relay 312f-en'ergized, the circuit of relay 300fis opened atfthevr outer-*left are mature and back-contact offY relayf 312 and relay.' 300: thereupon; deenergifzes: Being slow torelease, however, la-tteryf-i's'connected to the ring conductor 323 only during the releasing period of relay 300 for the purpose oi' tripping machine ringing at the'A incoming selector switch 200. This circuit for tripping machine ringing may be traced from battery through the outer left armature and iront contact oi' relay 312, resist- Y ance 321, the right armature and front contact ot relay 300, conductor 322, conductor 323, bank. terminal 222 and brush 221 of fina-l selector switch 250, the up per contacts of cam 216, bank terminalv 235 and brush 215 of incoming selector 200, the lower contactv of c ain- 214 ('11 to 14)", the right armature and' front contact of relay 201, the left contacts oi'- cam 202 (11 to 13) the windingl of marginal relay 230 and"y tok the source oi' rin-ging current 231. Relay 230 now receives' siiilicient currentto cause its energization and' is in'-l st'runiental' in` cutting oit the ringing cuirent and advancing sequence switch; 232 to the talking position in the manner hereinbefore described. The releasing time of relay 300, however, is so adjusted that batteryl current is disconnected fromeonductor 323" marginal relay 317, the outer leftarmature and irontv contact ot ringing reliayv3-14, conductor 318 thence over the subscribersf line loop throughs the ringer 3191,- returning over conductor 320 to ground at the inner lett armaturey and front contact of relay' 3114. Upon the response of the called' subscriber and the removal of his receiver fromits switchhook,marginal relay 317 receives sufli'- cient current' to cause its energization, whereupon the holding circuit' .of ringing relay 314 is" opened and relayl 314 becomes deenergized, disconnecting the source of ringing current from the subscrib'ersf linea llpon't'her deenergization offrelay 314, the initial" energizing circuit of relay 312 is opened andl relay 3011 isf connectedv with the conduct-ors 318 and 320 ofthe called line'. Talking current islnowI supplied tothecalled subscriber-s substation over a" circuit which may be traced `from 'battery' through the right winding ot' relayy 301, the innermost left armature a-nd` contact' of relay 312, the inner lef-t armature and" back contact of' relay 314, conductor 320, thence over tllefsubscribersline-loop', and'y returningthrough the outer left armature and back contact of relay 314 to ground through the left windinO oi rela 301. Rela 301 now enereizes calling subscriber releases the selector switches 150', 200 and 250.

The calling subscriber has now established a talking connection `with the called subscribers line C and the response of the called subscriber has had no eect upon the supervisory relay 219, since the external line con ductors 318 and 320 of the called line are separated from the conductors 308 and 323 extending to the right windings of repeating coil 220 through the winding of supervisory relay 319, by means of condensers 324, 325 and 326. Since the supervisory relay 219 is not energized current is not reversed through the windings otpolarized relay l179 at the district selector and consequently no -message registration circuits are prepared i'or operating the subscribers message register 112.

Upon the termination ,of the conversation and the restorationof the calling subscribers receiver to its switchhook, the line switch 106, district selector 150, incoming selector 200 and final selector 250y are restored in the well-known manner and as hereinbefore described. Upon the restoration of the iinalV selector switch250, the circuit previously traced from battery over bank terminal 239, and thence to ground through the winding of relay 304 is opened, and relay 304 becomes deenergized. Upon the restoration of the called subscribers receiver to its switchhook, rrelay 301 deenergizes opening its armature contact thereby disconnecting battery from the conductor 305. Since nowboth relays 304 and 301 are deenergized, the holding circuits for relays 303, 312 and cut-off relay 307 are opened, and these relays thereupon deenergize, All of the circuits employed in establishing the connection are now in normal condition.

1f the free line subscriber C initiatesA a call the line switch individual to his line leaves normal position in search of an outgoing trunk extending to a district selector in the manner hereinbefore described in connection with subscribers line A. When the line switch leaves normal position battery current is connected through the off-normal the test brush 238,V

contacts 327 of the line switch, through resistance 306, conductor 305 to ground through the winding of make-busy relay 303. This relay, upon energizing, disconnects the winding et sleeve relay 304 `from and connects battery potential to the multiples of test terminal 239 in the banks of all iinal select-ors having access to the subscribers line, over a circuit which may be traced from battery, through resistance 328, the left armature and back contact of relay 304,the armature and front contact of relay l303, conductor 240, thence to multiples of terminal239. The subscribers line C is thus marked busy to all final selectors having access thereto.

lf a subscriber in a manual office wishes 'a connection with the subscribers line C,

for which no charge should be made, he first obtains a connectionwith the manual operator at the position indicated at O, Fig. 4, who, upon ascertaining the number of the line desired proceeds to obtain the assignment of a tr'unk circuit extending to a cordless operators position of theinachine switching oiiice in which the desired subscribers line terminates. Upon receiving the assignment of the trunk, the operator inserts thc plug 241 of her cordcircuit in the jack 242 ot' the assigned trunk circuit, whereupon a circuit is established from battery through the winding of sleeve relay 243 to ground over the sleeve conductors of plug 241 and jack 242. Relay 243, upon energizing, bridges the supervisory relay 244 across the strands of the cord circuit.. A circuit is now established from battery through the right winding of relay 248, the normal right contacts of relay 249, the lower left winding of repeating coil 251, ring contacts of jack 242 and plug 241, the normal contact of ringing key 247, winding'of supervisory relay 244, armature and contact of relay 243, normal contact of ringing key 246,- tip contacts of plug'241 and jack 242, the upper left winding of repeating coil 251, the left armature Aand back contact or' relay 249 to ground through the left winding of relay 248. Relay 248 energizes in this circuit and in the manner fully set forth in the application of J. lV. Gooderham, Serial No. 417,422, Patent inb'efore referred to, causes the illumination of the-lamp 252 to apprise the cordless operator that she may proceed to set up the designation of the desired line upon the keyboard of her sender and initiate the establishment of the through the medium of the cordless incoming selector 260 and the final selector 270.

' Upon the seizure of the called lin'e C by the nal selector switch 270, a circuit is established from battery through test brush 257 and the bank terminal upon which it is resting, conductor 258, the winding of relay No. 1,506,743, heredesired connection p repeating coil 251, the winding' 310, the normal contacts of relay 303, to ground through the winding of sleeve relay 304. Relays 310 and 304 become energized, relay 304 causing the operation of relays 303YY and 367 in the manner previously described.v Relay 310 upon energizing opens the circuit previously traced through the winding of relay 300 to prevent the operation of this relay since upon a call ot this character it is not necessary to tripV niachine ringing. As relay 300 does not energize, relays 312 and 314 dornot energize and therefore ringing current is not appliedto thecalleld subscribers line from the source 316. Y

' Upon the establishment of the connection from the operators position G to the desired subscriber-s line C, the operator throws the ringing keys 246 and 247 Vfor establishing a ringing circuit from the source 263, which may be traced overthe alternate contact-of key 247, ring contacts ot plug 241 and jack 242, the lower left winding ot of ringdown relay 262, the upper left winding of repeating coil'251, tip contacts oi jack 242 and plug 241',V to ground at the alternate contact lof key 246. VRing-down relay 262 responds to the ringing current and closes .a circuit from battery through Y the lett winding of Yrelay 249, the armature and condensers 325 and contactof relay 262Y to ground wind-ingof ringing'relay259. Relay 249 energizes inthiscircuit disconnecting the windings of relay 248 from the left windings oi' repeating Vcoil 251 whereupon the circuit of relay 244 of theoperatoi"s cord circuit is maintained open after the release ofv ringing keys 246 and'247. Relay 248, however, is maintained energized overV a circuit extending from battery through its right winding to ground at the right armature and front Contact of relay 249. Upon the energiaation of ringing relay 259. in vseries with relay 249, ringing current is applied to `the line of the called subscriber from the source 261'over. the lower armat'ui'e and front Contact of relay 259, brush 255 and bank terminal of incoming selector switch. 260, brush 256 and bank terminal of final selector switch 270 conductor 330, 326, conductor 318', and thence, over the. subscribers. line loop tlirougliringer 319, returningover conductor 320, condenser 324,.conductor 329,Y bank terminal and brush 253 of final selector switch .270, bank terminal and brush A254 of incoming selector' switch 260, to ground at the upper armature .and front Contact of relay 259.

Upon the response of the called subscriber during the silent interval when ringing relay 259 is decnergized, a circuit is established ior supervisory relay 264, which may be through the ttracod from battery through the right winding of relay'264, the lowerright winding of repeating coil 251, the lowerl armature and back contact of relay 259, thence as previously traced over tliercalled subscribers line loo-p, returningthrough the normal contacts associated with the upper armature of relay 259, the upper right winding oi repeating coil 251 to ground through the left winding ot relay/,264. Upon the encrgization of supervisory relay 264, a circuit is established troni ground at the armature and Contact of relay 24S through the armature and contact ot relay 264 and the right winding of relay 249 for maintaining relay 249 energized.

Upon the termination of the conversation and the resto-ration of the subscribers receivers to their switch-hooks, the apparatus en'iployed is restored in the: following manner: Upon the restoration of the calling subscribers receiver to its switchhook, the operator. at position O receives the usual disconnect signal. 7 hen the called subscriber restores his receiver to-its'switchhook, the circuits previously traced through the windings ot relay 264 are opened. Relay 264 upon deeuergization, opens the holding circuit through the right winding of relay 249 and-since at this time the circuit through its lett winding is opened at the contacts of ringdown relay relay 249 deenergizes reconnecting the windings of relay 248 Vto the left windings ot repeating coil 251 landthereby recstablishing the circuits-through the supervisory relay 244 at the operators position. lVith relay 244 energized, the Acircuit of: the cal-ling supervisory lamp'245 isi-closed.V As at this time, both the answering and calling supervisory lamps are lighted, the operator proceeds to release' the connection by withdrawingthe` plug 241 from the jack 242. From this point-'the apparatus employed in establishing the connection restores in the well-known manner.

lhat is claimed is:

1.7In a telephone exchange system, a calling line, Va called line, a second called line, call charging lmechanism associated with said calling line, switching means for eX- tending a connection from said calling lineY to either of said called lines, means associated with said switching means for applying ringing current to the line called,ineans associatedy with said switching means for operating said `call charging mechanism following the successful establishment ot a connection-between said calling line and one of said called lines, a relayindividual to Y the other of said called lines operative upon the seizure thereof, a second relay operated thereby-for opening the circuit of said first relay, and a circuit controlled jointly by said relays for rendering said ringing current applying means inoperative, and for rendering ineffective said call charging operating means.

uio

2. In a 'telephone exchange'system, a calling line, a called line, a second called line, call charging mechanism associated with said calling line, switching means for extending a connection from said calling line to either of said called lines, means associated with said switching me-ans for applying ringing current to the line called, means'associated with said switching means for operating said call charging mechanism following the successful` establishment of a connection between said calling line and one of said called lines, a slow releasing relay individual to the other of said called lines operative upon seizure thereof, a second relay operated thereby for opening the circuit of said first 'relay and a circ-uit ointly controlled by said relays and effective during the releasing pe riod of said first relay for rendering said ringing current applying means inoperative, said circuitbeing'closed for a period insufficient to operate said call charging operating` means.

3. VIn a telephone exchange system, a calling line, a called line, a second called line, call charging mechanism associated with said calling line, switching means for extending a connection from said calling line to either of said called lines, means associated with said switching means for applying ringing current to the line called, means associated with said switching means for operating said call charging mechanism following the successful establishment of a connection i between said calling line and one of said called lines, a relay individual to the other of said called lines and operative over one conductor of said line upon the seizure thereof, a second relay operated thereby for opening the circuit of said first relay, and a circuit established over ano-ther conductor of said line under the joint control of said relays for rendering said ringing current applying means inoperative, and for rendering ineffective said call charging operating means.

4t. In a telephone exchange system, a calling line, a called line, a second called line, call charging mechanism associated with said calling line, switching means for extending a connection from said calling line to either of said called lines, a source of ringing current, means associated with said switching means for applying current from said source to the called line, means associated with said switching means for operating said call charging mechanism following the successful establishment of a connection between said calling line and one of said called lines, means individual to the other of said called lines for applying ringing current from said source directly to said line, a relay for controlling said last means and operative upon the seizure of said line, means controlled by said relay for rendering said first named ringing cur- 'rent applying means inoperative, and for rendering ineffective said call charging operating means, and means operative upon the response of the called subscriber to completely disconnect said source of ringing Vto either of said called lines, a source of ringing current, means associated with said switching means for applying current from said source to the called line, means associated with said switching means for operating said call charging mechanism following the successful establishment of a connectioii between said calling line and one -of said called lines, a slow releasing relaj,l

individual to the other of said called lines operative upon the seizure thereof, a second relay operated thereby for applying ringing current from said source directly to said line, a thirdrelay controlled by said second relay for opening the circuit of sai-d first relay, a circuit jointly controlled by said first and third relays and effective dur ing the releasing period of said first relay for rendering said first named ringing cur rent applying means inoperative, and for rendering ineffective said call charging operating means, and means operative upon the response of the called subscriber to completely disconnect said source of ringing current.

G. In a telephone exchange system, a calling line, a called line, a second called line, call charging mechanism associated with said calling line, automatic switching means for extending a connection from said calling line to either of said called lines, means associated with said switching means for applying ringing current to the line called, means associated with said switching means for operating said call charging mechanism following the successful establishment of a connection between said calling line and one of said called lines, condensers interposed in the other of said called lines between the substation thereof and said switching means, a relay individual to said latter called line operative upon the seizure thereof for rendering said ringing current applying means'inoperative, and rfor rendering ineffective said call charging operating means, and means on the outgoing side of said condensers for supplying talking current tothe substation of said called line.

7. In a telephone exchange system, a calling line, a called line, a second called line, call charging mechanism associated with said calling line, automatic switching means for extending a connection from said calling line to either of said called lines, means associated with said switching means for applying nringing current to the line called, means associated with said switching means for operating said call charging mechanism followingthe successful establishment of a connection between said calling line and one of said called lines, a relay individual to said latter called line operative upon the seizure thereof for rendering said ringing current applying' means inoperative, and for rendering .ineiliective said call charging operating means, a battery feed relay individual to said called line through which talking current is supplied to said called line, and means controlled by said latter relay for marking` said called line busy to all other switching,r means having'access thereto.

8. In a telephone exchange system, a calling' line, a called line, asecond called line, call chargingmechanism associated with said calling' line, automatic switching means for extendingv a connection trom said eall ing line to either oit said called lines, means associated with sai-d switching, mechanism for applying ringing current to the other called line, means associated with said switching means for operatingV` said call charging meehanism following the 4successful establishment of a connection between said calling line and one ofsaid Called lines, means individual to the :other of said called lines andjeffective for a period sufiicient to render said ringing currentvsupplying means ineffective, but for a period in suiiicient to operate said ca ll charging operatinpv means, semi-automatic switching meansjor extending a connection to either of said called lines, and means operative upon the seizure of said second called line through said semi-automatic switchingr means for rendering said individual means inoperative. Y

In witness whereof, I hereunto subscribe my name this 24th day of November, A. D.,

DAVID L. TEMPLE. 

